Study of mesozoic stratigraphic oil–gas reservoir of Yuqia–Hongshan fault sag in north margin of Qaidam basin

Yuqia-Hongshan fault sag is a Sub–tectonic Unit of Northern Margin of Qaidam Basin. On the basis of reserch about the Jurassic source rock, reservoir, cap rock of this fault sag. It is concluded that the source rock is mainly consist in the middle–lower Jurassic stratum, and it has the characteristics of big thickness and high abundance of organic matter. The better reservoir of Yuqia region is mainly distributed in the middle–fine sandstone formation of braided river face and braided river delta face and the better reservoir of Hongshan region is located on middle and lower Jurassic and Quanyagou-lower Cretaceous. In general, Yuqia-Hongshan fault sag mainly form reservoir–cap combination with the features of lower–generation and upper–reservoir, self–source and self–reservoir. Besides, reservoir is relatively thin, abundant, scattered and complex.